05000423/LER-2023-002, Auxiliary Feedwater Control Valve Failure Resulting in a Condition Prohibited by Technical Specifications
| ML23334A152 | |
| Person / Time | |
|---|---|
| Site: | Millstone  (NPF-049) |
| Issue date: | 11/30/2023 |
| From: | O'Connor M Dominion Energy Nuclear Connecticut |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 23-296 LER 2023-002-00 | |
| Download: ML23334A152 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4232023002R00 - NRC Website | |
text
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station 314 Rope Ferry Road, Waterford, CT 06385 DominionEnergy.com U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 NOV 3 0 :2023 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3 LICENSEE EVENT REPORT 2023-002-00 A, Dominion ij? Energy Serial No.:
23-296 MPS Lie/JP RO Docket No.: 50-423 License No.: NPF-49 AUXILIARY FEEDWATER CONTROL VALVE FAILURE RESULTING IN A CONDITION PROHIBITED BY TECHNICAL SPECIFICATIONS.
This letter forwards Licensee Event Report (LER) 2023-002-00, documenting a condition that was discovered at Millstone Power Station Unit 3 (MPS3) on October 1, 2023. This LER is being submitted pursuant to 10 CFR 50. 73 (a)(2)(i)(B) as a condition prohibited by technical specifications.
There are no regulatory commitments contained in this letter or its enclosure.
Should you have any questions, please contact Mr. Dean E. Rowe at (860) 444-5292.
Michael J. O'Connor Site Vice President - Millstone Enclosure: LER 423/2023-002-00
Serial No.23-296 Docket No. 50-423 Licensee Event Report 2023-002-00 Page 2 of 2 cc:
U.S. Nuclear Regulatory Commission Region I 475 Allendale Road, Suite 102, King of Prussia, PA 19406-1415.
R. V. Guzman NRC Project Manager Millstone Units 2 and 3 U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 C2 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station
Serial No.23-296 Docket No. 50-423 Licensee Event Report 2023-002-00 ATTACHMENT LICENSEE EVENT REPORT 2023-002-00 AUXILIARY FEEDWATER CONTROL VALVE FAILURE RESULTING IN A CONDITION PROHIBITED BY TECHNICAL SPECIFICATIONS.
MILLSTONE POWER STATION UNIT 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
Abstract
On October 1, 2023 at 1022 hours0.0118 days <br />0.284 hours <br />0.00169 weeks <br />3.88871e-4 months <br /> with Millstone Power Station Unit 3 in Mode 1 at 100 percent reactor power, turbine driven auxiliary feedwater control valve for the A steam generator, 3FWA*HV36A, drove full close and then back to full open, without a demand to close. 3FWA*HV36A cycled from open to close and back to open on September 4, 2023 and October 5, 2023 without a demand to close. A past operability review determined that this reoccurring unexpected condition provides evidence that the valve may not be relied upon when needed to perform its designed safety functions for longer than allowed by Technical Specifications. The direct cause of failure was a degraded Target Rock controller/
positioner card, 3FWA*HY36A6. The card was replaced, calibrated, and the valve was retested satisfactorily. This report is being submitted pursuant to 10 CFR 50.73 (a)(2)(i)(B), as an operation or condition that was prohibited by the plant's Technical Specifications B
AFW CARD T020 YES
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- 3. LER NUMBER YEAR SEQUENTIAL NUMBER REV NO.
052 050 5
5 Millstone Power Station - Unit 3 423 2023 002 00
CORRECTIVE ACTIONS
The degraded Target Rock controller/positioner card, 3FWA*HY36A6 was replaced, calibrated, and the valve was tested satisfactorily. Additional corrective actions are being taken in accordance with the station's corrective action program.
PREVIOUS OCCURANCES There have been no similar events or conditions where Auxiliary Feedwater system was inoperable for longer than the technical specification allowed outage time over the last 5 years.
ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) CODES FCV FLOW CONTROL VALVE BA AUXILIARY/EMERGENCY FEEDWATER SYSTEM
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